Thanks for checking.Mayhem wrote:UA7 is indeed 74LS00PC on the chip.
Anyone diagnose a "poorly" Vic-1010?
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- eslapion
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Re: Anyone diagnose a "poorly" Vic-1010?
Be normal.
- mrr19121970
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Re: Anyone diagnose a "poorly" Vic-1010?
So what is the most likely logic chip causing this issue ? 74ls245 ?
Why would you say replace them all? If mayhem has an ic tester and a ic clip he can test them on the board in seconds.
Why would you say replace them all? If mayhem has an ic tester and a ic clip he can test them on the board in seconds.
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Re: Anyone diagnose a "poorly" Vic-1010?
Big use of the word "if" there
I'll connect her up and see what happens with DK and Lunar Leeper first.
I'll connect her up and see what happens with DK and Lunar Leeper first.
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- eslapion
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Re: Anyone diagnose a "poorly" Vic-1010?
The VIC-1010 has 2 different types of buffer chips unlike the VIC-1020 so it's impossible to tell.mrr19121970 wrote:So what is the most likely logic chip causing this issue ? 74ls245 ?
Because modern equivalents from the HCT family consume less than 1/10th the amount of power taken by 74LS family chips and its usually less trouble than trying to troubleshoot.Why would you say replace them all?
You can't check an IC when it is still attached to a board where other ICs can send disruptive signal - connecting an IC tester will power all the chips.If mayhem has an ic tester and a ic clip he can test them on the board in seconds.
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Re: Anyone diagnose a "poorly" Vic-1010?
Sorry for not coming back to this yet, real life and all. Hopefully soon!
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Re: Anyone diagnose a "poorly" Vic-1010?
Assuming the 1020 schematics is the same as the 1010 (I don´t have a 1010 schematics), the CRW line seems to be unidirectional and going through U1 twice (NOT+NOT). I am not sure why, but in the case the U1 chip isn't working, the RAM expansion would not work. If the 74LS244 or 74LS245 didn´t work, ROM would´t have worked either.mrr19121970 wrote:So what is the most likely logic chip causing this issue ? 74ls245 ?
Why would you say replace them all? If mayhem has an ic tester and a ic clip he can test them on the board in seconds.
That being said its not that many chips and they are rather cheap, so I would have replaced them all. Check the board between each desolder/resolder to see if it fixed things. You may even put in sockets to make it easier to swap chips in the future?
PS: Before desoldering a chip, try melting the solder of all the chips. The most common error is a cracked solder which does not show but results in a broken circuit. I would do that with the U1 first.
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Re: Anyone diagnose a "poorly" Vic-1010?
The schematics for the VIC-1020 are here: http://sleepingelephant.com/denial/wiki ... ic1020.gifKakemoms wrote:Assuming the 1020 schematics is the same as the 1010 (I don´t have a 1010 schematics), ...
If you look at the photos at the beginning of the thread, there are much more chips on the VIC-1010 so the schematics are definitely not the same.
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Re: Anyone diagnose a "poorly" Vic-1010?
The 1020 has 5 IC's. The 1010 has the same 5 IC's plus two additional 74LS365 hex buffers. Since we don't have the schematic, we can only guess at their use. The most obvious is to buffer the non-buffered lines on the 1020.eslapion wrote:The schematics for the VIC-1020 are here: http://sleepingelephant.com/denial/wiki ... ic1020.gifKakemoms wrote:Assuming the 1020 schematics is the same as the 1010 (I don´t have a 1010 schematics), ...
If you look at the photos at the beginning of the thread, there are much more chips on the VIC-1010 so the schematics are definitely not the same.
- eslapion
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Re: Anyone diagnose a "poorly" Vic-1010?
When you assume you make an a55 of U & Me...Kakemoms wrote:The 1020 has 5 IC's. The 1010 has the same 5 IC's plus two additional 74LS365 hex buffers. Since we don't have the schematic, we can only guess at their use. The most obvious is to buffer the non-buffered lines on the 1020.
Sorry... this one was too easy. But I would say this; there is no way to tell if the buffers are connected to different lines in a manner remotely similar from one device to the other.
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Re: Anyone diagnose a "poorly" Vic-1010?
Sorry, just been so busy with a bunch of other things, I haven't had a chance to get back to this. Hopefully soon, at least to see what happens when I try to run those double bank games.
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- Mayhem
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Re: Anyone diagnose a "poorly" Vic-1010?
When I get some moments, I really am going to get back to this!
Lie with passion and be forever damned...